Revealed: One-minute DIY test that can detect early stage Alzheimer's

If you're worried about getting Alzheimer's disease, a simple DIY test could help confirm or quell your fears.

Researchers from the University of Florida (UF) highlight that a decline in the sense of smell is an early warning sign of Alzheimer's, as damage to the brain regions responsible for scent processing can occur prior to tell-tale cognitive symptoms like memory loss or confusion.

With this in mind, they developed a test that anyone can perform at home using a dollop of peanut butter and a ruler.

Jennifer Stamps, who was a graduate student in the UF McKnight Brain Institute Center for Smell and Taste at the time, said peanut butter was selected because it is a 'pure odorant.'

This means it is a substance that only stimulates the sense of smell and does not activate the trigeminal nerve, which is responsible for the sensations of touch, pain, and temperature.

Other examples of pure odorants include anise, banana, mint and pine.

In the UF study, which was conducted in 2013 but recently resurfaced, patients who came to the clinic for testing also sat down with a clinician, a jar of peanut butter and a metric ruler.

The patient closed his or her eyes and mouth and blocked one nostril.

The clinician held the peanut butter at a distance from the patient's open nostril, using the ruler to mark the point at which the patient could detect the odor.

The distance was recorded and the procedure was repeated on the other nostril after a 90-second delay.

The clinicians running the test did not know the patients' diagnoses, which were not usually confirmed until weeks after the initial clinical testing.

The scientists found that patients in the early stages of Alzheimer's disease had a dramatic difference between the left and right nostril in detecting odor.

The left nostril in these patients did not detect the smell until it was an average of 10 centimeters closer to the nose compared to the right nostril.

This was not the case in patients with other kinds of dementia. Instead, these patients had either no differences in odor detection between nostrils, or the right nostril was worse at detecting odor than the left.

Of the 24 patients tested who had mild cognitive impairment, which can turn into Alzheimer's disease, 10 showed a left nostril impairment.

The researchers said more studies must be conducted to fully understand the implications.

Dr. David Sinclair, a professor of genetics at Harvard Medical School who was not involved in the study, told the Daily Mail that he believes the peanut butter and ruler test is a 'simple and inexpensive yet effective' way of testing for early-stage Alzheimer's disease.

Alzheimer's progresses over time, with each stage lasting a different duration. It can take about two years for the early stage to progress into the middle stage, or at least eight to 10 years from diagnosis to the late stages of the disease.

In the earliest stages, a poor sense of smell is often one of the first signs.

'Alzheimer's disease often affects brain hemispheres unequally and possibly the olfactory bulbs (the first structures in the brain to process smells) too,' Dr. Sinclair explained.

'In turn, this can mean that one nostril can become less sensitive to smell than the other.'

The use of peanut butter might prove problematic for patients with nut allergies, but Dr. Sinclair noted that a different substance can be used.

'In the future, there might be standardized Alzheimer's tests that mimic this one, using a specific quantity of a stable, non-allergenic odorant,' he explained.

Dr. Gayatri Devi, a clinical professor of neurology at the Zucker School of Medicine at Hofstra/Northwell in New York who was not involved with the study, told the Daily Mail that alternatives to could include banana, chocolate, cinnamon, lemon and onion.

This year, researchers from Mass General Brigham in Boston developed olfactory tests in which participants sniff odor labels that have been placed on a card to assess their ability to discriminate, identify and remember odors.

They found that participants could successfully take the test at home and that older adults with cognitive impairment scored lower on the test than cognitively normal adults.

The UF researchers said these types of tests could be used by clinics that don't have access to the personnel or equipment to run more elaborate tests required for a specific diagnosis.

However, Dr. Devi said the scent tests should not be done at home and should be performed 'within the proper context of a medical examination, as it was for the study.'

'In this age, when everyone is concerned about brain health and about developing a dementia, we don’t want these people to get worried and stressed because they can’t smell,' she said.

'DIY tests to diagnose Alzheimer’s are not recommended given the gravity of such a diagnosis and should really only be done in proper context.'

Alzheimer's disease is one of the most common forms of dementia and mostly affects adults over the age of 65.

It is believed to be caused by the development of toxic amyloid and beta proteins in the brain, which can accumulate and damage cells responsible for memory.

Amyloid protein molecules stick together in brain cells, forming clumps called plaques, while tau proteins twist together in fiber-like strands called tangles.

The plaques and tangles block the ability of the brain's neurons to send electrical and chemical signals back and forth.

Over time, this disruption causes permanent damage in the brain that leads to Alzheimer's disease and dementia, causing patients to lose their ability to speak, care for themselves or even respond to the world around them.

About 7million people in the US 65 and older live with the condition, and over 100,000 die from it annually.

The Alzheimer's Association estimates that by 2050, nearly 13 million Americans will be living with the disease.